Insect and Spider Identification: Help to identify this bug in swimming pool

Hi, I have an indoor pool, and I found one day about 15 of these things flying around the light. Wasn't sure where they came from, so I just vaccumed them up.

Then a few days later, I took the pool cover off and found 50 of them mostly dead some still alive. I'm freaking out,can someone help me figure out what these are and how to get rid of them? I dont think the chlorine is killing them?